Little is known about diffusion tensor image (DTI) findings of corpus callosum (CC) injury in patients with diffuse axonal injury (DAI). In the present study, we investigated the presence and extent of CC injury in patients with DAI. Twenty patients with DAI and 20 age-and sex-matched normal healthy controls subjects were recruited. Patients were divided into two groups according to the presence of a CC lesion on conventional brain MRI, namely, the CC (+) group (8 patients) and the CC (-) group (12 patients). DTIs were acquired using a sensitivity-encoding head coil at 1.5 T. The CC was divided into six mid-sagittal segments: the genu, rostral midbody, anterior midbody, posterior midbody, isthmus, and splenium. Fractional anisotropies (FA) and apparent diffusion coefficients (ADCs) were measured. FA values of all CC segments in DAI patients were significantly lower than those of controls (p < 0.001); whereas ADC values were either similar or marginally higher. FA values of the six sagittal segments in the CC (-) and (+) groups were significantly lower than those of controls, and ADC values were slightly higher, or showed no change. CC lesions may be present in DAI patients, irrespective of detection on conventional brain MRI. The authors suggest the probability that in cases of corpus callosum injury, DTI can offer a powerful means of detecting DAI.